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I.E.S. sound system

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The company who provide the P.A. system for the complete Brain Salad Surgery tour was I.E.S. It stands for 'International Entertainers Services Ltd.', and was headquartered in London. The subsidiary company was in Long Island, New York. It was started because groups could not play to more than 3000 people. There needed to be a sound system invented to cope with large crowds so money could be made in the rock and roll business.



David Hartstone, born 1937 in Mangapiko, New Zealand


David 'Dave' Hartstone was the owner of I.E.S. He explain how it 'works' in that time:
"We invented this system or more correctly 22 of them. There were lots of things that had to be invented that were simple not around:

1. A mixing console with at least 30 channels
2. An electronic crossover in stereo at least
3. Amplifiers to drive the system
4. Speakers and horns etc.
5. Bass bins and buck and boost transformers to power the system

We accomplished all this in 18 months, and the first system was for the Isle of Wright Festival with 600 thousand people. It was a total success.




Then came ELP some years later. I thought that quadrophonic sound would be just right for them. Greg Lake was totally agreeable and so it was built. Almost 200 tons of it as there were large festivals in the up coming tour of 77 dates in the U.S. and 26 in Europe. The quad pot had to be designed and built. Each channel had a quad pot and they could be linked to 4 output quad pots to play with. The whole thing had to be rehearsed, and each day there was a rehearsal with the band. It was a massive affair. It took 85 crew to assemble the sound system.

The whole concept was invented by us...the mixer out in the crowd down to the monitors. It was all new. Most of the groups were overwhelmed with the technology, and crews had to be trained to use the equipment. But Emerson Lake and Palmer were our dream group. They were co-operative and the sound was spectacular.


Yes applied the I.E.S. sound system in 1972

ELP's system varied in size, according to the dates they played. All the systems were modular. The amplifiers were Crown DC300's, the 3 way crossover was Mavis, manufactured by us, and the mixers were Mavis also manufactured by us and was in 3 parts. The mixer weight was half a ton. The Mavis line of products (which stood for Music Augmentation Voice & Instrument System) was a major leep forward in the sound business. ELP's Mavis was 30 channels in and 30 channels out. The 30 channels out would go into 24 track Ampex's, which would record the show live. We had 2 of these big machines and we recorded ELP with them sometimes, but Stewart Young was always at the mixer accompanied by someone from their record company and removed all tapes.

The idea of having the mixing consoles out in front of the stage, some 200 feet, was totally ours. We were also the first to build a sound mixer. The first Mavis built was a 15 channel in and 2 out in stereo.

Bill Hough (since deceased) was a very special person to me. Not only was he my head tech, but also a friend and confidant. I trusted him explicitly. He was a brillant man, who knew Disney's technichians, and had been the head R&D man for ITT and there wasn't anything he didn't know about the Hammond organ. Without him, I.E.S. would have been a lesser company. ELP wouldn't go on tour without him, due to the complicated equipment ELP used, and I was glad of it. I.E.S. ran for 10 years and had many employees. Although I designed all the sound equipment and the way it should look, Bill Hough did all the circuitry."

with friendly permission by David Hartstone





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